A. Field of the Invention
The present invention relates generally to communication systems and, more particularly, to systems and methods that provide automated directory assistance.
B. Description of Related Art
Conventional telephone directory assistance requires a large number of people at great expense. Conventional systems have attempted to automate some of the calls for the most frequently requested listings using speech recognition. A typical system requires a large effort on the part of experts to set up and maintain the system. For example, the experts first determine the few most frequently requested listings (FRLs) and then record and transcribe calls to human operators.
For each of the FRLs, the experts design a small grammar specifying the various ways that each listing might be said. This is necessary because people rarely ask for the listing by saying it exactly as it appears in the telephone directory. They leave out parts of the listing (e.g., “Sears” instead of “Sears, Roebuck and Company Department Store”). They insert extra words (e.g., “K-Mart Department Store” instead of “K-Mart”). They insert extraneous words (e.g., “Uh I want the number for Sears, please”). They abbreviate listings (e.g., “DMV” for “Department of Motor Vehicles”). They also use other names entirely (e.g., “The phone company” instead of “Verizon”).
It is very hard to predict what people will say for each listing. Therefore, the experts usually create a grammar from several real examples. This is labor intensive, however.
Typically, the experts group the grammars for each of the FRLs to make a grammar for all of them. This makes it possible to recognize requests for any of the FRLs as long as the request is phrased in one of the ways anticipated by the experts. Most requests, however, are not for one of the FRLs, but for some other listing. In this case, the conventional systems detect that the requested number is not one of the FRLs and route the call to a human directory assistance operator.
As a result, a need exists for an automated directory assistance system that automates a larger number of listings than conventional systems.